Multiple ink-delivery tubes are necessary in ink-jet printers that use multiple sources of ink (e.g., multicolor) separated from a reciprocal carriage-mounted printhead. The tubes must connect the ink sources to the printhead in order to deliver the necessary ink, and must be sufficiently flexible to bend with the quick, back and forth movement of the printhead. Because these tubes are flexible and free to bend, they tend to twist and become tangled with each other.
The materials from which the ink-delivery tubes are manufactured represents a compromise of the conflicting functions of the tube. The ultimate goal of the tube is to deliver ink from ink sources to the printhead mechanism. However, the tubes must be sufficiently stiff to withstand the violent back-and-forth motion of the printhead over the life of the printer and yet also be flexible enough to minimize the wear on the carriage. The tube material must also be inert and not react with-the ink or any of the ink constituents. Moreover, the tube material should minimize the diffusion of volatile ink constituents because maintaining the proper concentrations of the various ingredients in the liquid ink is important in maintaining print quality. Diffusion could ultimately result in the ink "drying out" in the tube.
Previously, the twisting tendency of flexible, ink-delivery tubes during carriage motion has been overcome by using a multi-channel ganged silicone tube in a Cannon BJC-800 and BJC-820 printer. The multi-channel ganged silicone tube fails to reduce diffusion of volatile ink constituents to any significant extent.